Conventionally, an X-ray phase contrast imaging apparatus is known. Such an X-ray phase contrast imaging apparatus is disclosed in Japanese Patent Laid-Open No. 2012-16370, for example.
Japanese Patent Laid-Open No. 2012-16370 discloses an X-ray imaging apparatus (X-ray phase contrast imaging apparatus) that images the inside of a subject using the phase contrast of X-rays that have passed through the subject. This X-ray imaging apparatus can image a light element object and a soft tissue of a living body that are unlikely to absorb X-rays by imaging the inside of the subject using the phase contrast of the X-rays instead of the amount of absorption of the X-rays.
This X-ray imaging apparatus includes an X-ray source, gratings, and an X-ray image detector. The X-ray source, the gratings, and the X-ray image detector are arranged side by side in this order in the irradiation axis direction of the X-ray source.
In this X-ray imaging apparatus, the arrangement of the X-ray source, the gratings, and the X-ray image detector is determined by mathematical formulas. In the mathematical formulas, it is necessary to substitute the pitches of the gratings and the wavelength of the X-ray source.